Turbo Tony

This is a really useful thread with lots of valuable information. I hope the OP's issues are resolved permanently now.

Quick question: the VCDS video shows a long term trim of 1.5%. Is that good for all vehicles, or just this particular engine type? I'm guessing the sensors are calibrated for the air requirements for each engine, so 0% means a perfect engine?

If this isn't the case, what should it be on an S8?

CWTech

As I feared, the check engine light saga continues. It's taken about 6 weeks since I had the fuel pumps changed but the CEL popped on again during acceleration. Same code as before too, Lean Condition Bank 1.

To add further mystery my fuel economy seems to be terrible. I'm averaging 13mpg in the city now when I used to get about 16-17.

I've taken the car back, yet again, to Audi and asked their tech to call me as soon as he gets the car. The only thing I can think is that I'm getting a vacuum leak which only shows itself under load. Most everything else has been done including MAF, O2 sensors, fuel pumps, and fuel filters. My patience grows thin.

MP4.2+6.0

Did you ever run down the 02 sensor wiring I pointed out previously to conclusion--before the connector that is? And/or was B1 S1 O2 sensor ever changed?

CWTech

I did look and couldn't find anything. I asked Audi tech to check as well and they said the same. Both pre-cat O2 sensors were changed about 800 miles ago.

Jack88

They plugged them back in tight, right?

CWTech

As far as I can tell. Besides, I'm not getting any codes for the 02 sensors themselves, just an odd lean condition bank 1 every few weeks.

MP4.2+6.0

No, I don't read it that way, but then I can only read the information shown in the thread. Look at the text again in your 5/13 post of the print out. As before, notice the word "open." As in, open circuit. Unless something has changed during your work, you may have broken physical wiring. If 02 since replaced but that code remains, inference is it ("open") is on the CAR side. Hence why I asked the question again about what work/fixes had been done since. There is a TSB for this on W12's that says the terminal connectors on the car side have solder/continuity issues, with fix being connector replacement. Was explained in prior response.

If BTW you have some other code now that says lean separate from this, really you need to post specific code(s). Only specific code info I see goes back to 5/13.

CWTech

Audi finally tore the top of the engine back down and found their previous tech messed up the valve cover gasket. Hopefully this saga has reached its end.

carl viking

Following this thread with interest. For the S4 I'm seeing the same thing - lean 17544 code, and we do have a slight oil leak at the valve cover (even after replacing gasket twice and checking that the cover is not warped).
That said - not crystal clear a valve cover leak brings a lean condition. I plan t build my own smoker and try to find any other intake vacuum leaks first.
Monitoring blocks 32 and 33 you can see that idle is worse than partial (which means more likely a leak versus a MAF), and right around 6% positive adjustment is when the MIL is set.
Which is a bit annoying since even Ross-Tech says +-10% is considered normal for today's cars.

CWTech

Excuse me, I did not mean valve cover, I meant intake manifold gasket. We'll see if this is the end. I'm getting the car back today.